The present invention relates to detection of the presence of a turbulent layer from wind velocity and density at an observation point in the atmosphere and, more particularly, to a turbulent layer detecting apparatus for detecting a turbulent layer from the wind velocity and density at two or more observation points in the atmosphere.
Hitherto, as this type of a turbulent layer detecting apparatus, there has been known the one disclosed in the publication of U.S. Pat. No. 5,117,689, in which the heat radiated by molecules in the atmosphere is received by a passive sensor to measure the altitude distribution of temperatures and potential temperatures, and to further measure the wind velocity distribution in the atmosphere. Based on the measurement results of the altitude distribution of the temperatures and the potential temperatures and the wind velocity distribution, the Richardson number, which is an index indicating the degree of the turbulence of the atmospheric layer, is calculated thereby to detect a turbulent layer.
However, in the apparatus using the method described above, it has been extremely difficult to perform the measurement of wind velocity and the measurement of temperatures and potential temperatures from the same received signal, so that at least two different transmitting and receiving sections have been necessary. This has been posing a problem in that the apparatus is inevitably expensive.
Furthermore, it is required to determine the distribution of the Richardson numbers in the atmosphere over numerous points in the atmosphere, presenting a problem in that a considerable amount of time is required for detecting a turbulent layer.
The present invention has been made in view of the above, and it is an object of the invention to provide a turbulent layer detecting apparatus that transmits the beams of electromagnetic waves, sound waves, or light waves into the atmosphere, receives the electromagnetic waves, sound waves, or light waves that have been scattered by particulates or the like at a plurality of observation points in the atmosphere, measures both wind velocities and densities at the plurality of observation points in the atmosphere on the basis of the received signals, and detects the presence of a turbulent layer in an atmospheric layer sandwiched between the plurality of observation points from the measurement results of the wind velocities and the densities, thus making the detecting apparatus less expensive and also allowing a shortened time required for detection to be achieved.
A turbulent layer detecting apparatus in accordance with the present invention is equipped with a transmitting section that transmits beams of electromagnetic waves, sound waves or light waves into the atmosphere, a receiving section that receives the electromagnetic waves, the sound waves, or the light waves that have been transmitted by the transmitting section and scattered by particulates or the like in the atmosphere, a wind velocity measuring section that measures a beam direction component of a wind velocity at two or more observation points on a beam from a received signal received by a receiving section, or a density measuring section that measures a density at two or more observation points on the beam, and a turbulent layer detecting section that detects the presence of a turbulent layer on the basis of the output of either the wind velocity measuring section or the density measuring section.
The wind velocity measuring section determines the wind velocity in a horizontal direction from the beam direction component of the wind velocity.
The difference in altitude between two adjacent observation points of two or more observation points is greater than the thickness of the turbulent layer to be detected.
The turbulent layer detecting section detects a horizontal wind velocity difference from the horizontal wind velocities at two adjoining observation points of two or more observation points on a beam so as to detect a turbulent layer from the size of the horizontal wind velocity difference, or measures the densities at two adjoining observation points at two or more observation points on the beam and measures the change rate in the density at the altitudes of the two adjoining observation points so as to detect a turbulent layer from the level of the change rate in the density.
The turbulent layer detecting section has a predetermined threshold value on the horizontal wind velocity difference, and determines that a turbulent layer exists if a horizontal wind velocity difference exceeds the threshold value.
The turbulent layer detecting section has a predetermined threshold value on the Richardson number, estimates a change rate in density from a known atmospheric density distribution, uses the estimated change rate in density and a measured horizontal wind velocity difference to calculate the Richardson number, and determines that a turbulent layer exists if the calculated Richardson number is smaller than the predetermined threshold value on the Richardson number.
The turbulent layer detecting section has a predetermined threshold value on the change rate in density, and determines that a turbulent layer exists if a measurement of the change rate in density is smaller than the threshold value.
The turbulent layer detecting section has a predetermined threshold value on the Richardson number, estimates a horizontal wind velocity difference from a known atmospheric wind velocity distribution, uses the estimated horizontal wind velocity difference and a measured change rate in density to calculate the Richardson number, and determines that a turbulent layer exists if the calculated Richardson number is smaller than the predetermined threshold value on the Richardson number.
The turbulent layer detecting section has a predetermined threshold value on the horizontal wind velocity difference and a predetermined threshold value on the change rate in density, and determines that a turbulent layer exists if at least one of the following conditions is satisfied, the conditions being such that a measurement of the horizontal wind velocity difference exceeds the predetermined threshold value on the horizontal wind velocity difference, and a measurement of the change rate in density is smaller than the predetermined threshold value on the change rate in density.
The turbulent layer detecting section has a predetermined threshold value on the Richardson number, uses a measurement of the horizontal wind velocity difference and a measurement of the change rate in density to calculate the Richardson number, and determines that a turbulent layer exists if the calculated Richardson number is smaller than the predetermined threshold value on the Richardson number.
The turbulent layer detecting section uses a measurement result of either the change rate in density or the horizontal wind velocity difference to detect a turbulent layer, and if it determines that a turbulent layer has been detected, then it verifies the presence of the turbulent layer by employing the other measurement result.
The transmitting section sequentially scans the direction of beams in the atmosphere, and the receiving section receives the scanned beams that have been scattered by particulates or the like in the atmosphere.
The wind velocity measuring section measures the beam direction component of the wind velocity at two or more observation points on the beam, and the density measuring section measures the density at two or more observation points on the beam at each point in the process of scanning the direction of the beam.
The wind velocity measuring section determines the horizontal wind velocity from the beam direction component of the wind velocity at each point in the process of scanning the direction of the beam.
The altitude difference of two adjoining observation points of two or more observation points is greater than the thickness of a turbulent layer to be detected.
The turbulent layer detecting section detects the horizontal wind velocity difference between the upper and lower layers of an atmospheric layer at respective portions of the atmospheric layer from the horizontal wind velocities at the observation points on a beam at each point in the process of scanning the direction of the beam, and detects the presence of a turbulent layer in each portion of the atmospheric layer from the magnitude of the horizontal wind velocity difference, or measures the densities at the observation points on the beam at each point in the direction of the beam in the process of scanning the beam, and measures the change rate in density in each portion of the atmospheric layer so as to detect the presence of a turbulent layer in each portion of the atmospheric layer from the level of the measured change rate in density.
The turbulent layer detecting section has a predetermined threshold value on the horizontal wind velocity difference, and determines that a turbulent layer exists if a horizontal wind velocity difference exceeds the threshold value.
The turbulent layer detecting section has a predetermined threshold value on the Richardson number, estimates a change rate in density from a known atmospheric density distribution, uses the estimated change rate in density and a measured horizontal wind velocity difference to calculate the Richardson number, and determines that a turbulent layer exists if the calculated Richardson number is smaller than the predetermined threshold value on the Richardson number.
The turbulent layer detecting section has a predetermined threshold value on the change rate in density, and determines that a turbulent layer exists if a measurement of the change rate in density in each portion of the atmospheric layer is smaller than the threshold value.
The turbulent layer detecting section has a predetermined threshold value on the Richardson number, estimates a horizontal wind velocity difference from a known atmospheric wind velocity distribution, uses the estimated horizontal wind velocity difference and a measured change rate in density to calculate the Richardson number, and determines that a turbulent layer exists if the calculated Richardson number is smaller than the predetermined threshold value on the Richardson number.
The turbulent layer detecting section has a predetermined threshold value on the horizontal wind velocity difference and a predetermined threshold value on the change rate in density, and determines that a turbulent layer exists if at least one of the following conditions is satisfied, the conditions being such that, in each portion of the atmospheric layer, the horizontal wind velocity difference at observation points located in the upper and lower layers of the atmospheric layer exceeds the predetermined threshold value on the horizontal wind velocity difference, and a measurement of the change rate in density at the observation points located in the upper and lower layers of the atmospheric layer is smaller than the predetermined threshold value on the change rate in density.
The turbulent layer detecting section has a predetermined threshold value on the Richardson number, uses a measurement of the horizontal wind velocity difference and a measurement of the change rate in density at the observation points located in the upper and lower layers of the atmospheric layer in each portion of the atmospheric layer to calculate the Richardson number, and determines that a turbulent layer exists if the calculated Richardson number is smaller than the predetermined threshold value on the Richardson number.
The turbulent layer detecting section performs the detection of a turbulent layer by employing the measurement result of either the change rate in density or the horizontal wind velocity difference between the upper and lower layers sandwiching the atmospheric layer. If the turbulent layer detecting section determines that a turbulent layer has been detected, then it verifies the presence of the turbulent layer by employing the other measurement result.
The transmitting section has a function for transmitting two or more beams of electromagnetic waves, sound waves, or light waves, and the receiving section receives electromagnetic waves, sound waves, or light waves generated by being scattered by particulates or the like in the atmosphere.
The wind velocity measuring section measures the beam direction component of wind velocity at observation points on each of two or more beams, and the density measuring section measures the density at observation points on each of two or more beams.
The wind velocity measuring section determines the horizontal wind velocity from a beam direction component of a wind velocity at the observation points on two or more beams.
The positions of at least two observation points among the respective observation points on two or more beams are the two locations in a direction perpendicular to the surface of the earth.
The distance between the two locations in the direction perpendicular to the surface of the earth is greater than the thickness of a turbulent layer to be detected.
The turbulent layer detecting section detects a horizontal wind velocity difference between the upper and lower layers of an atmospheric layer in each portion of the atmospheric layer from the horizontal wind velocity at an observation point on each of two or more beams, and detects the presence of a turbulent layer in each portion of the atmospheric layer from the magnitude of the horizontal wind velocity difference, or measures the density at an observation point on each of two or more beams, and measures the change rate in density in each portion of the atmospheric layer so as to detect the presence of a turbulent layer in each portion of the atmospheric layer from the level of the measured change rate in density.
The turbulent layer detecting section has a predetermined threshold value on the horizontal wind velocity difference, and determines that a turbulent layer exists if a horizontal wind velocity difference exceeds the threshold value.
The turbulent layer detecting section has a predetermined threshold value on the Richardson number, estimates a change rate in density from a known atmospheric density distribution, uses the estimated change rate in density and a measured horizontal wind velocity difference to calculate the Richardson number, and determines that a turbulent layer exists if the calculated Richardson number is smaller than the predetermined threshold value on the Richardson number.
The turbulent layer detecting section has a predetermined threshold value on the change rate in density, and determines that a turbulent layer exists if a measurement of the change rate in density is smaller than the threshold value.
The turbulent layer detecting section has a predetermined threshold value on the Richardson number, estimates a horizontal wind velocity difference from a known atmospheric wind velocity distribution, uses the estimated horizontal wind velocity difference and a measured change rate in density to calculate the Richardson number, and determines that a turbulent layer exists if the calculated Richardson number is smaller than the predetermined threshold value on the Richardson number.
The turbulent layer detecting section has a predetermined threshold value on the horizontal wind velocity difference and a predetermined threshold value on the change rate in density, and determines that a turbulent layer exists if at least one of the following conditions is satisfied, the conditions being such that, in each portion of the atmospheric layer, the horizontal wind velocity difference at observation points located in the upper and lower layers of the atmospheric layer exceeds the predetermined threshold value on the horizontal wind velocity difference, and a measurement of the change rate in density at the observation points located in the upper and lower layers of the atmospheric layer is smaller than the predetermined threshold value on the change rate in density.
The turbulent layer detecting section has a predetermined threshold value on the Richardson number, uses a measurement of the horizontal wind velocity difference and a measurement of the change rate in density at the observation points located in the upper and lower layers of the atmospheric layer in each portion of the atmospheric layer to calculate the Richardson number, and determines that a turbulent layer exists if the calculated Richardson number is smaller than the predetermined threshold value on the Richardson number.
The turbulent layer detecting section performs the detection of a turbulent layer by employing the measurement result of either the change rate in density or the horizontal wind velocity difference between the upper and lower layers sandwiching the atmospheric layer. If the turbulent layer detecting section determines that a turbulent layer has been detected, then it verifies the presence of the turbulent layer by employing the other measurement result.
The predetermined threshold value on the Richardson number is 0.25.